In modern dairy farm industry there are continuous research and development activities in order to improve the efficiency of various activities such as machine milking, which, inter alia, involves increased milk yield and reduced milking time, while, is naturally, ethical aspects as well as animal care are considered.
Machine milking, as known in the art, generally utilizes teat cups and vacuum sources to perform the milking function. In such systems each teat is contained within a teat cup having a teat receiving liner, inside the teat cup next to the teat. A working vacuum is applied to the interior of each teat cup liner to draw the milk from the teat, with the teat liners periodically opened and collapsed by applications of a pulsating massage vacuum between the liner and the inside of the cup. This periodic working of the teat liners results in the periodic flow of milk from each teat into a milk line, and constitutes the actual milking of the cow.
U.S. Pat. No. 4,011,838 by Nordegren et al. discloses a milking machine system including a flow rate sensing device, a timing device, and a system control means for varying the character of the working and pulsating massage vacuums during the milking process, in response to the rate of milk flow and to time. The milking machine system can be controlled in predetermined phases, such as a stimulation phase, a milking phase, a post-milking phase, and a switch-off phase, with the duration of the phases dependent on the rate of milk flow reaching certain predetermined levels and on time lapse parameters.
U.S. Pat. No. 5,054,425 by Grimm et al. discloses a method of milking an animal, wherein the conditions of the milking operation are substantially stable during a main milking phase and are unintentionally changed during a terminating milking phase. According to the invention, at least one unintentional change in the milking operation conditions during at least one initial milking operation is sensed, at least one milking parameter is registered in response to the sensed unintentional change, and each registered parameter is utilized to change the milking conditions of one or more following milking operations for the same animal before each sensed unintentional change is expected to occur. By the invention the milking may be changed during the post-milking phase to obtain an elimination of or at least a significant reduction of the rest milk in the udder of the animal.
European Patent No. 0954962 B1 discloses a method of automatically milking animals, comprising the following steps: measuring repeatedly or continuously a quantity which is a measure for the momentary pulse milk flow; controlling the duration and/or the level of the milk vacuum under the teat during the actual suction phase on the basis of the measured quantity; storage, during the actual suction phase, of the maximum value of the pulse milk flow measured thus far or the quantity related thereto; and lowering or reducing or closing off the vacuum level of the milk vacuum as soon as the momentary value of the pulse milk flow or the quantity related thereto has come below a specific, preferably adjustable threshold value.
German Patent Application Publication No. 3609275 A1 discloses a method for mechanically drawing off milk. When milk is mechanically drawn off, the change over time of the milk flow from each individual teat is measured within individual pulse cycles and evaluated mathematically in a process computer. This evaluation of milk flow profiles permits the computer to provide actuating variables for controlling or adjusting parameters governing the application of the vacuum to the teat cup cluster, for example the level of vacuum in the suction phase, the duration of the suction phase and the like.